The invention relates to a rack-and-pinion steering for vehicles, including a toothed rack having a longitudinal axis, a toothed rack housing in which the toothed rack is guided for axial displacement between two end stops, and an end stop damping assembly which includes at least one stop ring and at least one elastic compression body, the compression body surrounding the toothed rack, and its spring/damping section having an axial length in a non-loaded condition. The stop ring has a continuously surrounding axial guide extension which is located radially inside in relation to the compression body and which has an axial length.
Such a rack-and-pinion steering having the features of the generic portion of claim 1 is known from WO 03/029067 A1, and corresponding U.S. Pat. No. 7,258,035 B2, both of which are incorporated by reference herein in entirety, for example. The end stop damping assembly here includes two bushings that are angled to form flanges and an elastically flexible material, the bushings that are fitted into one another and the flanges thereof forming an approximately hollow cylindrical chamber which fully encloses the elastically flexible material. While one of the bushings is firmly installed in a housing, the other can be moved axially in relation to a toothed rack axis, whereby the elastically flexible material is compressed in the region of an end stop and the end stop is struck in a damped manner. In a variant embodiment of the steering, the bushing that is firmly installed in the housing may also be integrated in one piece in the housing.
In the end stop damping of rack-and-pinion steering systems it is, in principle, desirable for the damping assembly to be structured as simply as possible and to allow to be mounted with minimum effort while requiring a small amount of structural space. In addition, it is of particular importance that the damping assembly with the elastic compression body has a suitable damping or spring characteristic.
In WO 03/029067 A1 the end stop damping assembly features a very steep characteristic. This makes the end stop fairly hard, which leads to high stress on the component and may also cause damage to the rack-and-pinion steering over the long service life.
EP 1 777 138 A1, in contrast, discloses an end stop damping assembly for a rack-and-pinion steering in which elastic compression bodies are connected in series. From this series connection and the almost unlimited possibilities of deformation of the compression bodies there results a very flat characteristic, i.e. a fairly soft end stop. Accordingly, a large deformation path is required in order to provide a sufficient counterforce for braking the toothed rack. The damping assembly therefore takes up an undesirably large amount of structural space and, due to the series connection of the compression bodies with stabilization members interposed, further leads to considerable manufacturing expenditure.